basics of computers

1. Data Representation
Analog Signals
• Analog signals are continuous in nature, they carry information in the
form of waves e.g., the way sound travels in the medium such as
telephone lines.
• Analog communication uses general purpose communication
channels.
• These signals are characterized by two parameters such as amplitude
and frequency
Figure : Analog Signal
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2. Data Digital Signals
Representation
• Digital signals are discrete in nature.
• They transfer information in the form of 0s and 1s.
• In digital communication, data are transmitted directly in binary form that
is a sequence of 0s and 1s. To transmit binary data over these channels
0s and 1s should be converted to the electrical signals. This is done by
Modem (modulator-demodulator).
• Digital signals are preferred over analog signals. Because of the discrete
nature, these signals are not affected by noise or any other disturbances.
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3. Data Representation
Digital Signals Cont…
Figure : Digital Signal
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4. Data Representation
Bandwidth
• Bandwidth is the frequency range of a channel, measured as the difference
between the highest and lowest frequencies that the channel supports.
• Bandwidth is the capacity for a given system to transfer data over a
connection. It is measured as a bit rate expressed in bits/s or multiples of it
(kb/s Mb/s etc.).
• The maximum transmission speed depends upon the available bandwidth.
• The larger the bandwidth, the higher the transmission speed.
• A normal voice channel has a bandwidth of 3.1 KHz. In real life scenario, it is
equivalent to about 1200 bps max. for a binary digital signal.
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5. Data Representation
Applications of Networking
• Resource Access: Regardless of the physical location of the resources
and the users, networks can provide special computing resources with
convenient access at any time to its users. These resources sharing may
be of specialized computers, software or other devices that are expensive
or unique. For example accessing a corporate supercomputer from
workstations at remote research laboratories
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6. Data Representation
Applications of Networking
cont……
• Data Access: Networks can provide access to unique database to its local
and remote users.
• Communication and Data Exchange: Networks allow users to exchange
data, graphs or documents and to communicate using email, bulletin
boards or by teleconference, irrespective of the time or their location.
4. Decentralization of Data Processing: A complicated job can be divided into
multiple modules and can be distributed to different departments for
processing.
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7. Data Representation
Applications of Networking
cont……
5. Easy Communication: Various organizations cooperating in a task can
communicate with each other on network and exchange information.
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